Adiantum.pptx(intoduction,species,reproduction)

ADIANTUM

1. Adiantum ​ Guided by- Dr . Uday Chitnis sir

2. Introduction 2 Classification Characteristic Structure Reproduction Lifecycle KEY POINTS

3. Introduction Adiantum, the maidenhair fern is a genus of about 250 species of fern in the subfamily vittarioideae of the family Pteridaceae , though some researchers place it in its own family, Adiantaceae . The genus name comes from Greek, meaning “unwetted”, referring to the fronds ability to shed water without becoming wet. They generally prefer humus rich, moist, well-drained sites, ranging from bottomland soils to vertical rock walls. Many species are especially known for growing on rock walls around waterfalls and water seepage areas. The highest species diversity is in the andes . Fairly high diversity also occurs in eastern asia , with nearly 40 species in china . 3

4. Presentation title 4 ADIANTUM (HABIT)

5. Scientific Classification 5 Kingdom: Plantae Clade : Tracheophytes Division: Polypodiophyta Class: Polypodiopsida Order: Polypodiales Family: Pteridaceae Subfamily: Vittarioideae Genus: Adiantum L.

6. Characteristics They are distinctive in appearance, with dark, often black  stipes  and  rachises , and bright green, often delicately cut leaf tissue. The  sori  are borne submarginally, and are covered by reflexed flaps of leaf tissue which resemble indusia.  Dimorphism between sterile and fertile fronds is generally subtle . Adiantum pedatum , fern which typically grow 1.5 to 2 tall and is most frequently found on rich wooded slopes, ravine bottoms and damp shady woods.  Rhizome is a perennial, subterranean dichotomously branched structure and is creeping in  A. capillus -veneris  or may be erect as in  A. caudatum . The roots are adventitious and arise from the rhizome.  The leaves are also called fronds and are pinnately compound the young leaves are circinately coiled. The petiole is long, black and shiny. The venation is free and dichotomous in all the species. The vein spread in a fan-like manner in the lamina. The leaves bear marginal sori which are covered by a  false indusium. 6

7. The rhizome in transverse section shows a single layered epidermis covered by cuticle. Some epidermal cells bear multicellular hairs. The Epidermis is followed by two to three layered hypodermis made up of sclerenchyma tissue. A parenchymatous ground tissue is present. The young rhizomes have amphiphloic siphonostele. The older rhizomes have solenostele or dictyostele . 7 Internal structure Root   The root is differentiated into epidermis, cortex and central vascular cylinder. The epidermis is the outermost layer and bears unicellular root hairs. The cortex is divided into outer wide parenchymatous and inner narrow sclerenchymatous layer. The stele is simple and possesses a central core of xylem in diarch condition with phloem on either side of it  . Rhizome

8. Petiole The petiole in T.S. shows a single layered epidermis with thick cuticle. Epidermis is followed by a sclerenchymatous hypodermis which provides mechanical support. There is an extensive parenchymatous ground tissue. The central region possesses a single large horse shoe shaped stele. Xylem forms central core surrounded by phloem.  Pinnule The Pinnule shows upper and lower epidermis. The cells contain chloroplasts. Stomata are confined to lower epidermis. The mesophyll is not differentiated into palisade and spongy parenchyma. The vascular bundle is surrounded by sclerenchymatous bundle sheath. 8

9. 9 Reproduction Adiantum  is homosporous. The   reproduction takes place by the production of spores. The spores are produced in sporangia. A group of sporangia forms sori. The sori are marginal but the reflex margins of the pinna form a protective membranous structure called   false   indusium  . The development   of sporangium is of leptosporangiate type. The sorus does not show any definite sequence hence fall under mixed type. A mature sporangium bears a multicellular stalk and a spherical or elliptical single layered structure called  capsule . The capsule contains haploid spores. The wall of the capsule is differentiated into thick walled annulus and thin walled  stomium . On maturity the sporangium bursts and spores are released. The spores germinate and undergo repeated division to produce a  prothallus . The prothallus is flat, green and heart shaped. It is monoecious and represents the gametophytic phase. Sex organs called  antheridia  and  archegonia  develop on the prothallus. Antheridia release multiflagellate antherozoids which swim in water and reach the egg of the archegonium to accomplish fertilization. 

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11. 11 Species of Adiantum Adiantum species: A -B( A. pseudotinctum ) A. Frond. B. Pinnules abaxially. C.( A. pentadactylon ) Habit D-F ( A. sinuosum ) D. Habit. E. Young plant. F. Sori. G-I ( A. glaucescens ) G. Frond. H. Pinnules abaxially. I . Sori  

12. Thank you Presented by-Lalima evane